As a testament to its continued popularity on its 50th anniversary, the "Sound of Music" is ready to hit more than 500 theaters in April and 20th Century Fox Home Entertainment has released a five-disc set of the movie with a new documentary on the film.

The Academy Award-winning musical was nicknamed "The Sound of Money" during its run in the mid-1960s, according to the Pittsburgh Post-Gazette, playing in theaters for more than four years, long before the advent home video.

The movie's 50th anniversary was recognized at this year's Academy Awards with Lady Gaga singing a stirring medley of its songs and with "The Sound of Music" star Julie Andrews greeting her at the end.

"It is extremely good storytelling," Barry Monush, author of "The Sound of Music FAQ," told the Post-Gazette. "I mean, I think Robert Wise deservedly won that Academy Award for best director."

"And the casting of Julie Andrews is pivotal, it's just pivotal. ... Somehow she manages to make that character so real and never cloying. I really think she's an essential part of why people fell in love with the movie," Monush said.

Christopher Plummer, who became an Academy Award winner in 2012 for his role in "Beginners," told Vanity Fair this month that he would only later become comfortable with his role as Captain Von Trapp in the film.

"As cynical as I always was about 'The Sound of Music,' I do respect that it is a bit of relief from all the gunfire and car chases you see these days," said Plummer. "It's sort of wonderfully, old-fashionedly universal."

Andrews said she will always remember the film because it was the time "everything exploded" for her, doing "The Sound of Music" and "Marry Poppins."

"This one stuck because it was very well made with beautiful music and a lot of glorious assets like scenery and mountains and children and an adventure story and a love story and all of that," Andrews told The Associated Press of her theory about the movie's staying power.

As a testament to its continued popularity on its 50th anniversary, the "Sound of Music" is ready to hit more than 500 theaters in April and 20th Century Fox Home Entertainment has released a five-disc set of the movie with a new documentary on the film.